Fisher Price TRIO Gears Set TRIO gears provides more ways for kids to build their creativity and easily add motion to their creations Kids can hear and feel the click when they make a connection Custom pares include: 3x3 gear block, gear pivot, gear propeller, 1 inch gears, 3 inch gears, 1 inch gears with C1 block top and a Crank gear All pieces in the TRIO building system work together TRIO building sets help children refine their eye-hand coordination and fine motor skills